With his time as governor winding down, Jerry Brown has been in legacy protection mode. He has staved off fellow Democrats’ expensive programs to protect reserves that he could build to $17 billion next year. He has defended Proposition 57, the 2016 ballot measure he embraced to make it easier for prisoners to win parole, which opponents have already targeted with a 2020 ballot measure. And he has got a fight on his hands to combat Proposition 6, the repeal of a gas tax increase he signed last year.

Now The Sacramento Bee reports that the governor has directly appealed to California Supreme Court Chief Justice Tani Cantil-Sakauye to expedite the court’s review of a lawsuit that challenges the Public Employee Pension Reform Act, a 2012 law that he championed. The lawsuit, filed by the union representing state firefighters, seeks to undo a key provision of the pension law: its ban on “air time,” which lets workers buy additional years of service to boost their pensions upon retirement.

If the court sides with Brown, that would be a huge win for the pension reform movement. That’s because it would undermine what’s known as the “California Rule.” This is a judicial precedent that generally holds that public employee pensions cannot be reduced in any way without affected employees receiving additional compensation to cover their lost income. The rule creates an immense obstacle to meaningful changes in retirement benefits for already-hired workers. Given that it was created by judges — not the California Legislature — it deserves no deference from the state’s high court.

Brown’s likely successor — Lt. Gov. Gavin Newsom — has already said he will support retention of the California Rule no matter how courts rule, so it’s no wonder the governor wants the state Supreme Court to act before his January exit. But if Brown really wants to help local and state government agencies deal with extreme pension costs, he should also push justices to back the city of San Diego in its Supreme Court pension fight. That’s because San Diego’s loss in court would set a precedent making it much harder to cut retirement benefits even for public employees who haven’t been hired.

San Diego’s fight involves Proposition B. The successful 2012 ballot measure required that new city hires — outside of police officers — receive 401(k)-style retirement benefits, not traditional defined-benefit pensions. City unions say that then-Mayor Jerry Sanders’ role as a leader of the campaign violated their rights to collectively bargain changes in employment contracts, and state justices appeared to agree at oral arguments in May.

This contention is questionable. Labor-law expert Tim Yeung argues that it simply “doesn’t make sense” to consider an individual elected leader’s lobbying for citizen-driven ballot measures as always being tantamount to an official action.

But that’s not the only reason the California Supreme Court should hesitate to overrule the decisive vote of San Diegans. If justices create a precedent that says elected leaders must steer clear of ballot measures that affect their public employees, then the imbalance of power in the Golden State between public employee unions and taxpayers will become even more skewed. Because of their popularity, elected officials have played a key role in direct democracy since it began in California in 1911.

If this potent tool to take on the state’s most powerful special interests is diminished, that will be awful news for all Californians — not just San Diegans. If Gov. Jerry Brown cares not just about his legacy but the future of his home state, he should make this point loudly and clearly.